1. Field of the Invention
The present invention relates to a paper note discrimination method which facilitates identification processing by efficiently compressing and encoding the image data of paper notes such as bills (paper money) and checks when discriminating the paper notes.
2. Description of the Prior Art
In conventional bill discrimination machines equipped with an image line sensor for collecting the image data of the entire surface of a bill and performing the bill discrimination, in the case where an attempt is made to discriminate not only three types of Japanese bills but also foreign bills at the same time, there is a bill discrimination machine where reference image data, usually called a template, is prepared and where the reference image data and the image data of another bill to be discriminated are compared to judge the paper money type, direction of transport, and authenticity.
However, in such a conventional general discrimination method, the data of a minute area is processed to perform an accurate identification, as described for example in Japanese Patent Laid-Open No. 260187/1992. Also, in the case where optical data is employed, it is conditioned in many cases that the value of the optical data does not exceed the upper limit of a reference value and that such optical data is greater than the lower limit of the reference value. In addition, since a large quantity of data are processed for the bill, there are many cases where an image area predetermined for each type of paper money is specified to raise a processing speed and where the features of only that area are extracted to judge the paper money type or the like.
In the aforementioned discrimination methods, in the case where the number of types of the bills to be handled is increased, the respective specified areas are different and there is the need to find out the specified area for each bill, so there is the problem that additional time for development to find out specified area for each bill is required. Also, resolving the image data into multiple values has become one of the main causes which lengthens the processing time. Furthermore, in the case where there is the need to discriminate a variety of bills with the same discrimination machine, there is a desire for a paper notes discrimination method which reduces a requisite memory size and yet can perform the bill discrimination at a high speed.